The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
One such membrane module includes an elongated filter element, which is penetrated by at least one longitudinal conduit and comprises a porous material, such as ceramic. The module further includes a housing, which surrounds the filter element and with it forms a collection chamber.
Such a module functions as follows: Into one end of each longitudinal conduit, the medium to be treated, the so-called unfiltrate, is introduced. Along the course of the unfiltrate, filtrate passes through the wall surface of the longitudinal conduit, enters the aforementioned collection chamber between the filter element and the housing, and is carried away from there as filtrate. The unfiltrate emerges from the other end of the longitudinal conduits and is optionally returned to the first end of the longitudinal conduit, so as to form a cycle. The wall surfaces of the longitudinal conduits are coated with a material that is also permeable to a certain extent. This usually very thin film usually forms the actual filtration device.
A single filter element has a plurality of longitudinal conduits (multi-conduit element). A plurality of such multi-conduit elements is combined to form a membrane module from them.
On each face end of the filter elements, there is a face-end plate. It defines the annular chamber between the housing and the filter elements, specifically in such a way that the annular chamber is sealed off from the outer environment at least in fluid-tight fashion. Sealing it off can be problematic, since during operation varying temperatures prevail, which lead to expansion and contraction of structural parts, in fact in different ways. The face-end boundary plates may for instance be of special steel.
Exemplary embodiments have become known from EP 0 270 051 B1 and DE 690 19 552 T2. EP 1 374 979 A2 describes a filter membrane module having a multitude of spaghetti-type individual filter capillaries, which are bundled at theirs ends by means of a potting material. DE 600 24 966 T2 discloses a thermoplastic filter cartouche with a plurality of concentric filter tubes. US 2008/0035270 A1 relates to a filter membrane module having a multitude of fibers, the ends of which are bundled by means of a potting material. US 2007/0144716 A1 describes a device with porous membranes, the ends of which being unitarily combined by potting.